Make no mistake about it: when Afghan “insiders” turn their weapons on their U.S. and coalition allies and kill them, most either escape or are killed in the act. So gleaning intelligence about motivation can be tough. Forty NATO troops, including 25 Americans, have been killed in such “green-on-blue” attacks this year.

But even given the thin evidentiary gruel, it has been surprising to see the varying Pentagon assessments of what share of these attacks are being conducted by Taliban infiltrators, as opposed to just generally ticked-off Afghan troops motivated by anger, petulance or other real or perceived slights.

Let’s review the data.

A reporter asked Marine General John Allen, who commands most U.S. and allied troops in Afghanistan, about those attacks in May.

Allen said:

It’s important to note that in the analysis that we have done, less than 50% of the ones that have perpetrated these attacks were in fact Taliban infiltrators. Many of these folks are self- radicalized. So it’s important to understand and be able to recognize the nature of that self-radicalization in the ranks.

“Less than” is one of those weasel phrases loved by generals…and reporters. Most folks only hear “50%” and tend to ignore the qualifier.

Allen dealt with the same issue Thursday, when he spoke to reporters at the Pentagon in a video link from Afghanistan:

We don’t have enough data from those who have participated in the attacks to be able to make any kind of a definitive conclusion. We think the reasons for these attacks are complex. Some of them, we do believe, are about infiltration, impersonation, coercion. But some of them — and we think that’s about 25% or so.

Bob Burns, the AP’s ace Pentagon correspondent, said the 25% figure didn’t square with what Pentagon officials have been saying:

The Pentagon just a few days ago told us that your folks had looked at this and come up with a number around 10%. I’m wondering how you can explain the difference?

Allen responded:

Our view is it’s about 25%…this still requires a lot of analysis. And so if it’s just pure Taliban infiltration, that is one number. If you add to that impersonation, the potential that someone is pulling the trigger because the Taliban have coerced the family members, that’s a different number. And so it’s less about the precision of 25 versus 10 than it is acknowledging that the Taliban are seeking, ultimately, to have some impact in the formation. And Bob, I know you are aware that the Taliban try to take credit for every one of these attacks, whether it’s a personal grievance or whether it was a successful infiltration.

Allen’s NATO headquarters later said the lower figure referred only to 2012 attacks, while Allen’s 25% included all such attacks since 2007. So, there you have it: whatever the share of Taliban-influenced attacks is today, it seems – by General Allen’s own accounting – to be less than it was three months ago, even as insider attacks have spiked.